Ingot mold



raie'n'ted July 7,1936

fUNITED STATES PATENT OFFICE INGOT MOLD Emil Gathmann, Baltimore, Md.

Application August 2, 1934, Serial No. 738,128

y `7 Claims. (Cl. 2l39l This invention relates to ingot molds and more particularly to ingot molds having vertically extending chamber-denning walls necked-in at their bottoms, of the kind shown for example in my prior United States Patents 1,188,751 oi .lune 27, 1916; 1,660,037 oi Feb. 2i, 1928; 1,573,486 oi Feb. 16, 1926; 1,570,473 oi Jan. 19, 1926 and others well known in the art.

In my Patent 1,188,751, referred to above, 1 have disclosed and claimed a metallic ingot mold the lower portion oi which has concave walls which merge with convex walls the latter in turn being tangent to and merging with the walls oi an opening extending vertically through the mold bottom. This general type oi `bottom contour has been employed in. many thousands oi tons of molds used in the commercial production oi ingots, these molds having been found to produce a consistently high grade ingot both as regards the crystalline structure oi the lower end o1 the ingot and the ease with which the ingot can be handled during the rolling process, particularly during the initial mill passes.

A practical dimculty with molds oi' the kind disclosed in the patents referred to above is that because oi the lower or convert walls being tangent to or merging with the wallsoi the mold bottom opening and having rather small radii, (i. e. small as compared to the mean width oi the mold chamber proper), there is provided a hump or protuberance extending around and just above the moldbottom opening which is particularly vulnerable to the cutting action oi the hot liquid steel as it splashes laterally from the closure within the bottom opening. This has resuited in premature erosion oi the convex portion and consequently in shortened mold life, since cutting away of this part of the mold wall results in poor surface at the bottom of the ingot. This has been objected to by steel makers for a number of years but has been put up with as part ofthe necessary additional cost of producing the kind ci ingot desired.

.an object of the present invention is to eliminate as far as possible this localized and premature erosion or cutting away oi the portion oi the mold wall surrounding vand Just above the mold bottom opening, yet providing a bottom contour which will produce ingots having the improved qualities of ingots produced in molds of the kind disclosed in the prior patents referred to.

Generally stated, my invention consists in the provision of a mold having a chamber-detinlng wall which is necked-in at its bottom, terminating in u. vertically extending mold bottom opening, the necked-in Deltion oi the wall comprising a. concave part which merges with the mold wall proper and a preferably convex part connected to 5 the concave part and intersecting butnot being tangent to the Wall oi the mold bottom opening, the arrangement being such that the objectionable hump or protuberance previously relerred to is practically eliminated. In its more specinc nature the invention resides in the provision oi a bottom contour embodying a specically novel and improved arrangement oi curved vvall kportions having radii bearing specihc relative proportions to each other and to other dimensions oi l5 the mold. f

'The invention `vvill be more clearly understood from a reading oi' the. following description oi a typical embodiment, the appended claims, and the accompanying drawing, in which: 20

Figure l is a vertical sectional view of a mold .embodying the invention, the section being taken on the line l-l o1' Figure 3;

Figure 2 is a vertical sectional view taken on the line d--t or Figure 3; t5 Figure 3 is a horizontal sectional view taken on the line 1 1 oi Figure 1; and

Figure d is a fragmentary vieu' in vertical cross 'section taken on the line i--l oi Figure 3 and Vdrawn on an enlarged scale.

For the piume oi illustration the drawing shows a big-end-up mold M of the Gathmann type generally rectangular in horizontal cross section and having side Walls i which are corrugated in horizontal cross section, although it will be t5 understood that the invention may be embodied in molds having other horizontal sectional con1 tours. The Walls l are connected by corner walls t, the Walls i and i being continuous and thereiore together constituting a mold wall proper extending around andA dening the mold chamber. The bottom of the mold is formed with a centrally disposed bottom opening 1 the Width a of which preferably is relatively small as compared to the approximate mean Width b oi the mold chamber. For example, in the mold shown the width a may be about one-third the width b. A closure plug P of a well known kind is shown positioned in the opening 9.

The wall l-2 is necked-in at its bottom, the 50 necked-in portion X terminating at the mold bottom opening, and in accordance with one feature of the invention, the necked-in portion intersects the upper marginal edge of the bottom opening as at 3'; i. e., the necked-in portion, if 55 as indicated by the dotted lines 3.

The necked-in portion X comprises a concave part] which merges with the mold wall proper I-2, a substantially straight, (i. e straight in vertical cross section) inwardly tapered part 5 which is tangent to the concave part 4, and a convex part 6 which is tangent to and merges with the substantiallystraight part 5 and which intersects the bottom opening 3 at its upper marginal edge 3'. It is important in order to avoid the fonnation oi a hump or protuberance around the top of the opening 3 that the convex part d shouldkr not be tangent to the wall of the opening-in other words, the convex part should intersect the upper marginal edge of the opening, and the continuation 32 of the convex part should extend towlthin the opening 3. To provide this desired arrangement I employ a convex part 6 having a radius R atleast as long as the radius R' of the concavepart 4 and preferably a little larger, and I locate the centers C and C' ofthe curved parts 6 and l in general accordance with the arrangement shown in Figure 4.

It will be understood that the specific lengths of the radii and positioning of the centers may vary depending somewhat upon the speciilc size and type of mold. By way oi! example, however, in the mold shown, which has a chamber approximately sixty-four inches in height and about twenty inches in mean width b, the following dimensions are preferred: The width a of the top of the bottom opening 3 is about six inches and the depth d of the opening may also be about six inches. 'I'he radius R of the concave part I is about three and one-half inches and is located a distance e (about six inches) above the top o1' the bottom opening 3. 'I'he length of the radius R is about tive inches and the center C is located a distance f (about three and one-half inches) below the top oi' the bottom opening 3 and a` distance y (about six inches) from the vertical center line oi' the bottom opening. Preferably the radius R is about one-fourth as long as the mean width b of the mold chamber and the radius R' is about lone-sixth as long as b. The bottom walls of molds having a bottom' contour such as described herein have been found to be much less susceptible to the cutting action of the molten steel than molds having contours such as those disclosed inthe prior patents referred to.

Obviously the numerical dimensions stated above will vary in molds oi' different sizes and it will be understood that the invention resides in the provision of the kind of mold bottom contour described herein and particularly pointed out in the appended claims.

I claim:

1. An ingot mold having a vertically extending chamber deiined by a wall which is necked-in at the bottom terminating in a mold bottom opening or relatively small width as compared to the width of the mold chamber, the necked-in portion of the wail comprising a concave part which merges with the moldwall proper and a convex part connected to the concave part and which, in section longitudinally of the mold, intersects but is not tangent to the wall of the mold bottom open- 2. An ingot mold having a vertically extending chamber defined by a wall which is necked-in at the bottom terminating in a mold bottom opening of relatively small width as compared to the width of the mold chamber, the necked-in portion lof the wall comprising a concave part which y y 2,047,093 vcontinen, would extend to within the opening a imerges with the mold wall proper and a convex ypart connected to the concave part and intersecting the upper edge oi' the wall of the mold bottom opening, the continuation of the arc of said convex part extending inwardly beyond the walls of 5 and into said mold bottom opening.

3. An ingot mold havinga vertically extending chamber .defined by a wall which is neckedin at the bottom terminating in a mold bottom opening of, relatively small width as compared to the width of the mold chamber, the neckedin portion of the 'wall comprising a concave'part which merges with the mold wall proper, a substantially straight inwardly tapered part tangent to said concave part, and a convex part 1s connected to the substantially straight part and intersecting the upper edge of the wall of the mold bottom opening, the continuation ot the arc oi said convex part extending inwardly beyond the walls of and into said mold bottomzo opening.

4. An ingot mold having a vertically extending chamber defined by a wall which is neckedin at the bottom terminating in a mold bottom opening ci' relatively small width as compared :s to the width of the mold chamber, the neckedin portion o! the walls comprising a concave part which merges with the mold wall proper, a substantially straight inwardly tapered part tangent to said concave part, anda convex part connected to the substantially straight part and intersecting the upper edge of the wall of the mold bottom opening, the continuation of the arc of said convex part extending inwardly beyond the walls of and into said mold bottom $5 opening, the radius of said convex part being at least as long as the radius of the concave part.

5. An ingot mold having a vertically extend.- ing chamber defined by a -wall which is neckedin at the bottom terminating in a mold bottom opening of relatively small width as compared to the width of the mold chamber, the neckedin portion o! the wall comprising a concave part which merges with the mold wall proper, a substantially' straight inwardly tapered part tangent to said concave part, and a convex part connected to the substantially straight part and intersecting the upper edge of the wall of the mold bottom opening, the continuation of the arc of said convex part extending inwardly beyond thev walls of and into said mold bottom opening, the radius of the convex part being longer than the radius of the concave part.

6 An ingot mold having a vertically extending chamber defined by a wall which is neckedin at the bottom terminating in a mold bottom opening of vrelatively small width as compared to the width of the mold chamber, the neckedin portion of the wall comprising a concave part which merges' with the mold wall proper, a substantially straightinwardiy tapered part tangent to 'said concave part, and a convex part connected to the substantially straight part and intersecting the upper edge of the wall oi' the mold bottom opening, the continuation of the arc oi' said convex part extending inwardly beyond the walls of and into said mold bottom opening, the radius of the concave part being about one-sixth as long as the mean width of 70 the chamber proper and the radius of theconvex part being about one-fourth as long as the mean width of-the chamber proper.

7. 4An ingot mold having a verticallyextending chamber dennedby a wall which is" necked- 75 intersecting but not being tangent to the-upper edge of the wallot the mold bottom opening, the

continuation of the line of said lower part ex.

tending into said mold bottom opening.

u mm. GA'rmsANN. 

